The present invention relates to a cold and warm pack for physiotherapy and the like with a tightly bonded or welded sleeve made from a flexible foil, film or sheet and a heat-storing or cold-storing filling.
Hot and cold compresses and poultices have long been used as a therapeutic aid in the treatment of bruises, strains and similar injuries and are highly esteemed by Doctors and patients, because they can be applied without difficulty to the parts of the body to be treated, prevent the formation of unnecessary swelling and rapidly act in a soothing manner. The same applies with regard to the packs of the aforementioned type, which have the advantage compared with the above-indicated compresses and poultices that they can be applied dry, which is appreciated by the patient.
Initially such packs filled with water, so that they could be heated or cooled without difficulty in water bath. A more pronounced or longer-lasting cooling action of such packs could be obtained by placing them in a refrigerator or deep-freeze. However, longer storage in a refrigerator or deep-freeze caused the contents to become solidly frozen, with the disadvantage that the originally flexible pack was converted into a rigid structure which, on application to an uneven surface, e.g. a knee joint, assumed non-uniform contact and consequently a non-uniform heat transfer. Therefore packs of the aforementioned type were developed, whose filling consisted of a glycol--water mixture, which did not change as rapidly into a rigid structure. However, such packs have not proved completely satisfactory in practice because it was also not possible to prevent in their case that the liquid content thereof would be non-uniformly distributed when placed on an uneven substrate, so that they fail to ensure a uniform heat transfer.
It has therefore been proposed to place a foam insert impregnated with a heat-storing or cold-storing fluid in the interior of the pack sleeve. However, as a result of the given shape of the foam insert, the ability of such a pack to adapt to an uneven surface is limited. In addition, this foam insert unnecessarily decreases the heat and cold storage capacity of the pack. The latter also applies with respect to those packs, whose interior contains closed-cell foam bodies, e.g. balls, in addition to heat or cold-storing fluid, because such foam bodies also reduce the heat or cold storage capacity of the pack. In addition, the known packs freeze when kept for long periods at below -15.degree. C.